The invention involves a process for evacuating a wet or liquid conveying medium out of the treatment chamber of a treatment device using a pumping device that has a single or multi-stage suction pump, where the conveying medium is cooled during the evacuation along the flow path such that the conveying medium in the pumping device is in the liquid aggregate state or is converted into that state.
The invention also involves a treatment device for carrying out the above-named process, having a treatment chamber, which is connected to a pumping device for evacuation, and a single or multi-stage suction pump, which is provided for the pumping device, where the pumping device can be cooled at least in a partial area using at least one cooling device such that the conveying medium in the pumping device is found in the liquid aggregate state or is converted into that state.
Furthermore, the invention also contains a single or multi-stage suction pump, especially for the treatment device described above, having at least one intake valve that is located in a pump head and at least one outlet valve, where at least one of these valves has a valve disc that is controlled by the conveying medium and which in the closed position of the valve fits so that it seals on a valve sealing surface of the pump head, which encloses at least one valve opening.
Treatment devices of this type are known for or example, as autoclaves for sterilizing medical items for daily use. These previously known treatment devices have an airtight sealable treatment chamber in which the instruments located therein are exposed prior to sterilization at first to a so-called fractionated pre-vacuum, in which through repeated evacuation of the air in exchange with the periodic incoming flow of steam, an especially good air removal out of the narrow-lumen instruments can also be achieved. During the sterilization operation, the instruments are exposed in the treatment or sterilization chamber to hot water vapor under partial vacuum. In order to quickly dry the instruments after sterilization so that there are no residues, a so-called post-vacuum is in turn created subsequently in the treatment chamber, which shortens the drying times of the sterilizing item and should optimize the drying operation.
For the evacuation, the sterilization chamber of these types of previously known steam sterilization devices is connected to a pumping device, which has a vacuum pump. Due to the impingement of the vacuum pump with water steam, thus far, only water ring pumps or diaphragm pumps have been used. Due to the structural dimensions and the disadvantages of a water ring pump, the smaller steam sterilization devices provided for a doctor's office, for example, usually utilize only diaphragm pumps.
For this reason, a treatment device constructed as a steam sterilizer, of the type noted above, has already been created. It has a pumping mechanism for the evacuation of the treatment or sterilization chamber, which utilizes a suction pump operated in a manner free from water, such that in the suction line provided between the treatment chamber and the suction pump, a water free cooled condenser is connected intermediately in order to convert the conveying medium flowing through the suction line of the pumping device into the liquid aggregate state. (See German Patent DE 44 45 054 C2).
In German Patent DE 44 45 054 C2, it is also described how the treatment chamber of the previously known processing device can be evacuated by opening a solenoid valve and switching on the suction pump at a predetermined pressure at the program start. Then, the solenoid valve is closed and steam is conducted from a steam generator into the pressure chamber until a preset excess pressure is reached. By again opening the solenoid valve and switching on the diaphragm pump, the steam/air mixture is in turn suctioned off to achieve a defined partial vacuum, such that the water vapor coming out of the treatment chamber condenses in a cooling device constructed as a condenser and is collected in a condenser collecting vessel so that the diaphragm pump of the previously known treatment device only pumps air.
In coupling a conventional diaphragm vacuum pump with a conventional autoclave, however, the following problem occurs: After the end of a sterilization operation, the steam is expelled through the vacuum pump via a connection line. In the cold connection line and the cold vacuum pump, at least a part of the steam condenses. This condensate is pumped off by the vacuum pump. It is a problem in this that during the operation in the area of the pump head that is heating up, a re-vaporization of the condensate can occur, so that then a correspondingly larger volume must be pumped off. This takes a considerable amount of time.
A re-vaporization of this type is also not ruled out by the fact that in the suction line provided between the treatment chamber and the suction pump, a condenser is intermediately connected. The problems caused by a re-vaporization of this type also occur, in addition to the autoclaves named at the beginning, for all other types, for example, in treatment devices used for gel drying, out of the processing chamber of which a wet or liquid conveying medium is to be evacuated. Here, a wet conveying medium is understood to be, for example, any gas or gas mixture which transports at least a partial quantity of a substance found in the form of a gas or vapor state or a drippable liquid state.